Bomb squad and canine units comb school grounds after bomb discovered only hours before commencement of school-day; school staff member suspected.

An explosive device was discovered on the grounds of Brener Junior High school in Petah Tikva late Tuesday night, police reported Wednesday morning.

The device was found in possession of a school custodian while a second suspect was arrested on the scene in connection to an ongoing drug investigation in which police had been surveilling the school grounds, according to a police statement.

The school custodian, 31, has not been connected to criminal organizations or underworld activity by police. Central District Police Chief Nitzav Yaacov Borotsky stated that the custodian had used his access to the school grounds to hide the explosive device but that the bomb was not intended for use against the school or its students.

Along with the two suspects and explosive device, police found drugs on the scene. Police suspected the second man at the scene was connected to the drugs and not the bomb.

Police were rushed to the premise late on Tuesday night when surveillance teams involved in the drug investigation made the decision to break cover after the bomb was discovered only ten hours before the start of classes on the following morning.

A bomb squad unit and canine units conducted extensive sweeps of the school and police have opened up an investigation into the incident. Borotsky added that a search for any other explosive material would continue until the grounds could be declared safe and classes could commence as usual.

"A real tragedy was prevented here today," Borotsky said about the potential danger that an explosive device posed in such close proximity to school children.

The bomb threat follows a similar incident in March when an explosive device was found on a Petah Tikva street corner. Police were called to the scene and subsequently located the detonator. A bomb squad neutralized the bomb after tenants in the adjacent building were evacuated.